AP1 ch 6

The following are important steps in the process of endochondral ossification. 1. Blood vessels grow around the edges of the cartilage and perichondrium differentiates into osteoblasts. 2. Capillaries and osteoblasts migrate to the epithyses forming the secondary ossification centers. 3. Chondrocytes enlarge and the surrounding matrix begins to calcify. 4. Remodeling continues and the shaft becomes thicker. 5. Blood vessels penetrate the cartilage and invade the central region forming the primary ossification center. What is the correct order for these events?

3, 1, 5, 4, 2

Define endochondral ossification. A) Endochondral ossification is the replacement of a cartilage model with bone. B) Endochondral ossification is the formation of fibrocartilage. C) Endochondral ossification is bone formation within connective tissue without the prior development of a cartilage model. D) Endochondral ossification is the formation of hyaline cartilage. E) Endochondral ossification is the formation of elastic cartilage.

A) Endochondral ossification is the replacement of a cartilage model with bone.

The shaft of a long bone is called the A) diaphysis. B) epiphysis. C) epiphyseal plate. D) metaphysis. E) lamella.

A) diaphysis

In bone, the calcium phosphate forms crystals of A) hydroxyapatite. B) calcium apatite. C) carbonite. D) osteocyte. E) calcium carbonate.

A) hydroxyapatite.

Which of the following would NOT be a way that parathyroid hormone (PTH) could alter plasma calcium levels? (Which one of the following is FALSE?) A) increase osteoblasts on bone B) increase osteoclasts C) increase reabsorption of calcium in the kidney

A) increase osteoblasts on bone

The process of osteolysis is performed by which cell population? A) osteoclasts B) osteocytes C) osteoblasts D) osteoprogenitor cells

A) osteoclasts

The carpal bones are examples of ________ bones. A) short B) sesamoid C) irregular D) long E) flat

A) short

A ________ is a smooth, grooved bone process shaped like a pulley. A) trochlea B) trochanter C) meatus D) tuberosity E) fossa

A) trochlea

Which condition, due to excessive cartilage formation at the epiphyseal cartilages, results in individuals who are very tall, with long, slender limbs? A) acromegaly B) Marfan syndrome C) achondroplasia D) gigantism

B) Marfan syndrome

Which of the following statements regarding the homeostasis regulation of blood calcium is FALSE? A) Calcitonin inhibits the action of osteoclasts while having no effect on osteoblast activity. This helps to lower the blood calcium level whenever it exceeds 11 mg/dL. B) The three main organs that serve as the site for the regulation of blood calcium levels are the bones, the intestines, and the pancreas. C) PTH is secreted by the parathyroid glands and raises blood calcium levels that are below 8.5 mg/dL. D) The homeostasis of blood calcium is regulated by a negative feedback mechanism.

B) The three main organs that serve as the site for the regulation of blood calcium levels are the bones, the intestines, and the pancreas.

Which hormone works directly in the intestine to increase plasma calcium levels? A) calcitonin B) calcitriol C) parathyroid hormone (PTH)

B) calcitriol

The most abundant mineral in the human body is A) hydrogen. B) calcium. C) phosphorus. D) sodium. E) potassium.

B) calcium

List the steps involved in fracture repair, beginning just after the fracture occurs. A) fracture hematoma formation, spongy bone formation, callus formation, compact bone formation B) fracture hematoma formation, callus formation, spongy bone formation, compact bone formation C) compact bone formation, spongy bone formation, callus formation, fracture hematoma formation D) callus formation, fracture hematoma formation, compact bone formation, spongy bone formation E) callus formation, spongy bone formation, fracture hematoma formation, compact bone formation

B) fracture hematoma formation, callus formation, spongy bone formation, compact bone formation

In a ________ fracture, one side of the shaft is split and the other side is bent. A) Colles B) greenstick C) compression D) Pott's E) comminuted

B) greenstick

A hard ossified bone in an adult actually begins within the embryo as a miniature version composed of __________. A) dense irregular connective tissue B) hyaline cartilage C) dense regular connective tissue D) elastic cartilage E) fibrocartilage

B) hyaline cartilage

Which of the following is true for parathyroid hormone? A) stimulates osteoblast activity. B) inhibits calcitonin secretion. C) decreases the rate of calcium absorption. D) lowers the level of calcium ion in the blood. E) increase the rate of calcium excretion.

B) inhibits calcitonin secretion.

Which of the following hormones is currently thought to decrease plasma calcium levels in pregnant women and children? A) thyroid hormones B) calcitriol C) calcitonin D) parathyroid hormone (PTH)

C) calcitonin

PTH promotes the formation of which hormone? A) thyroid hormones B) vitamin D C) calcitriol D) calcitonin

C) calcitriol

Which substance accounts for almost two-thirds of the weight of bone? A) collagen fibers B) osteocytes C) calcium salts D) fibroblasts

C) calcium salts

During the early stages of endochondral ossification, which cells enlarge, then die and disintegrate? A) osteoclasts B) osteoblasts C) chondrocytes D) osteocytes

C) chondrocytes

The hormone calcitonin A) stimulates osteoblasts and inhibits osteoclasts. B) decreases the rate of calcium absorption. C) decreases the level of calcium ion in the blood. D) stimulates osteoclast activity. E) decreases the rate of calcium excretion.

C) decreases the level of calcium ion in the blood.

Blood is distributed from the surface of a bone to deeper central canals through channels known as A) lamellae. B) trabeculae. C) perforating canals. D) concentric lamellae. E) osteons.

C) perforating canals.

Which class of bones develops inside tendons and is most commonly located near joints at the knees, the hands, and the feet? A) flat bones B) short bones C) sesamoid bones D) sutural bones

C) sesamoid bones

As blood vessels extend into the spaces left by dying chondrocytes, the models begin to ossify internally. Where does internal ossification begin? A) the primary ossification centers in the epiphyses B) the secondary ossification centers in the epiphyses C) the primary ossification center in the diaphysis D) the epiphyseal lines

C) the primary ossification center in the diaphysis

Which of the following bones is classified as "irregular" in shape? A) frontal B) patella C) vertebra D) metatarsal E) ulna

C) vertebra

Bill, age 15, is still growing, but his older sister Andrea, age 19, has stopped. What has changed in Andrea's bones? A) Sex hormones are no longer telling them to grow. B) They have more cartilage than Bill's. C) Her osteoblasts have died. D) Her epiphyseal plates have ossified.

D) Her epiphyseal plates have ossified.

Define intramembranous ossification. A) Intramembranous ossification is the formation of hyaline cartilage from mesenchymal cells. B) Intramembranous ossification is the formation of fibrocartilage from mesenchymal cells. C) Intramembranous ossification is the replacement of a cartilage model with bone. D) Intramembranous ossification is bone formation within connective tissue without the prior development of a cartilage model. E) Intramembranous ossification is the formation of elastic cartilage from mesenchymal cells.

D) Intramembranous ossification is bone formation within connective tissue without the prior development of a cartilage model.

Which of the following statements about Marfan's syndrome is false? A) It results from a mutation. B) It affects connective tissue genes. C) It affects epiphyseal cartilages. D) It results in short, stubby fingers. E) None of the answers is correct.

D) It results in short, stubby fingers.

________ free calcium from bone to maintain blood calcium levels. A) Osteogenic cells B) Osteoblasts C) Osteocytes D) Osteoclasts

D) Osteoclasts

Osteocytes are embedded in a dense matrix of hydroxyapatite. Which of the following describes how osteocytes receive nutrients? A) by osmosis from neighboring osteocytes. B) by diffusion from nutrients released from vessels in the central canal that travel through perforating canals. C) by diffusion directly from nutrients stored in the periosteum. D) by diffusion from nutrients released from vessels in the central canal that travel through canaliculi. E) by diffusion from neighboring osteoblasts cells traveling through lamellae.

D) by diffusion from nutrients released from vessels in the central canal that travel through canaliculi.

During the process of ________, an existing tissue is replaced by bone. A) osteolysis B) appositional growth C) perforation D) ossification E) deposition

D) ossification

Cells of the perichondrium need to take on a new role as ossification begins. They will become __________. A) new chondrocytes, so the model can continue to grow B) fibroblasts, to coat the model in collagen C) osteoclasts and dissolve cartilage matrix D) osteoblasts and begin to deposit bone matrix

D) osteoblasts and begin to deposit bone matrix

The lacunae of osseous tissue contain A) bone marrow. B) capillaries. C) blood cells. D) osteocytes. E) chondroblasts.

D) osteocytes.

Compare gigantism with acromegaly. A) Gigantism results from an overproduction of growth hormone during fetal bone development, whereas acromegaly results from an overproduction of growth hormone during childhood but before puberty. B) Gigantism results from an overproduction of growth hormone before puberty, whereas acromegaly results from an overproduction of growth hormone after puberty. C) Gigantism results from an overproduction of growth hormone before puberty, whereas acromegaly results from an underproduction of growth hormone after puberty. D) Gigantism results from an overproduction of growth hormone before puberty, whereas acromegaly results from an underproduction of growth hormone before puberty. E) Gigantism results from an overproduction of growth hormone after puberty, whereas acromegaly results from an overproduction of growth hormone before puberty.

E) Gigantism results from an overproduction of growth hormone before puberty, whereas acromegaly results from an overproduction of growth hormone after puberty.

The intestinal response to PTH secretion when calcium ion levels are low is that calcium is A) conserved. B) absorbed slowly. C) excreted. D) released. E) absorbed quickly.

E) absorbed quickly.

When the epiphyseal plate is replaced by bone, A) the bone becomes more brittle. B) interstitial bone growth begins. C) appositional bone growth begins. D) puberty begins. E) long bones have reached their adult length.

E) long bones have reached their adult length.

Cells that secrete the organic components of the bone matrix are called A) chondrocytes. B) osteocytes. C) osteoprogenitor cells. D) osteoclasts. E) osteoblasts.

E) osteoblasts